Purification and Characterization of a Cytochrome P450 Enzyme from Pig Liver, Catalyzing the Phenol Oxidative Coupling of (R)-Reticuline to Salutaridine, the Critical Step in Morphine Biosynthesis

Heterocycles ◽  
1995 ◽  
Vol 40 (1) ◽  
pp. 425 ◽  
Author(s):  
Meinhart H. Zenk ◽  
Tobias Amann ◽  
Peter H. Ross ◽  
Hoon Huh
Keyword(s):  
Cytochrome P450 ◽  
Oxidative Coupling ◽  
Cytochrome P450 Enzyme ◽  
Purification And Characterization ◽  
Pig Liver ◽  
Critical Step ◽  
P450 Enzyme

CYTOCHROME P450: Nature's Most Versatile Biological Catalyst

2005 ◽  
Vol 45 (1) ◽  
pp. 1-25 ◽  
Author(s):  
Minor J. Coon
Keyword(s):  
Cytochrome P450 ◽  
Enzyme System ◽  
Cytochrome P450 Enzyme ◽  
Purification And Characterization ◽  
P450 Enzyme ◽  
Microsomal Membranes ◽  
Cytochrome P450 Enzyme System ◽  
The Individual ◽  
Reaction Cycles

The author describes studies that led to the resolution and reconstitution of the cytochrome P450 enzyme system in microsomal membranes. The review indicates how purification and characterization of the cytochromes led to rigorous evidence for multiple isoforms of the oxygenases with distinct chemical and physical properties and different but somewhat overlapping substrate specificities. Present knowledge of the individual steps in the P450 and reductase reaction cycles is summarized, including evidence for the generation of multiple functional oxidants that may contribute to the exceptional diversity of the reactions catalyzed.

scholarly journals Characterization of Medicago truncatula (barrel medic) hydroperoxide lyase (CYP74C3), a water-soluble detergent-free cytochrome P450 monomer whose biological activity is defined by monomer–micelle association

2006 ◽  
Vol 395 (3) ◽  
pp. 641-652 ◽  
Author(s):  
Richard K. Hughes ◽  
Eric J. Belfield ◽  
Mylrajan Muthusamay ◽  
Anuja Khan ◽  
Arthur Rowe ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Cytochrome P450 ◽  
Medicago Truncatula ◽  
Water Soluble ◽  
Hydroperoxide Lyase ◽  
Cytochrome P450 Enzyme ◽  
Cytochrome P450 Enzymes ◽  
P450 Enzyme ◽  
Detergent Micelles

We describe the detailed biochemical characterization of CYP74C3 (cytochrome P450 subfamily 74C3), a recombinant plant cytochrome P450 enzyme with HPL (hydroperoxide lyase) activity from Medicago truncatula (barrel medic). Steady-state kinetic parameters, substrate and product specificities, RZ (Reinheitszahl or purity index), molar absorption coefficient, haem content, and new ligands for an HPL are reported. We show on the basis of gel filtration, sedimentation velocity (sedimentation coefficient distribution) and sedimentation equilibrium (molecular mass) analyses that CYP74C3 has low enzyme activity as a detergent-free, water-soluble, monomer. The enzyme activity can be completely restored by re-activation with detergent micelles, but not detergent monomers. Corresponding changes in the spin state equilibrium, and probably co-ordination of the haem iron, are novel for cytochrome P450 enzymes and suggest that detergent micelles have a subtle effect on protein conformation, rather than substrate presentation, which is sufficient to improve substrate binding and catalytic-centre activity by an order of magnitude. The kcat/Km of up to 1.6×108 M−1·s−1 is among the highest recorded, which is remarkable for an enzyme whose reaction mechanism involves the scission of a C–C bond. We carried out both kinetic and biophysical studies to demonstrate that this effect is a result of the formation of a complex between a protein monomer and a single detergent micelle. Association with a detergent micelle rather than oligomeric state represents a new mechanism of activation for membrane-associated cytochrome P450 enzymes. Highly concentrated and monodispersed samples of detergent-free CYP74C3 protein may be well suited for the purposes of crystallization and structural resolution of the first plant cytochrome P450 enzyme.

The role of cytochrome P450 enzyme genetic variants in cannabis hyperemesis syndrome—A case report

2021 ◽  
Author(s):  
Maxim Kuzin ◽  
Franziskos Xepapadakos ◽  
Isabel Scharrer ◽  
Marc Augsburger ◽  
Chin‐Bin Eap ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Case Report ◽  
Genetic Variants ◽  
Cytochrome P450 Enzyme ◽  
P450 Enzyme ◽  
Cannabis Hyperemesis Syndrome
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